Slide-valve oe steam-engines



sTATns PATENT ormoni.

STEPHEN F. GATES, OE BOSTON, MASSACHUSETTS.

f SLIDE-VALVE OF STEAM-ENGINES.

Specification of Letters Patent No.

To all wlwnz, l may concern Be it known that I, STEPHEN F. GATES, of Boston, county of Suffolk, and Commonwealth of Massachusetts, have invented a new and useful improvement in slide-valves for steam-engines and other purposes by diminishing the friction and relieving the pressure of the steam or fluid, as the case may be, on the valve as now used, and thereby forming a balance slide-valve; and I do hereby declare that the following is a full and exact description of the construction and operaw tion of the same, reference being herein had to the annexed drawings, which constitute a part of this specification.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

Description of the annexed dra/wings.- Figure l represents a vertical section o-f the steam chest, valve and a portion of the cylinder, as cut through at the line B, B. Fig. 2, represents a transverse vertical section of the same, as cut through at the line A, A. Fig. 3 represents a horizontal sect-ion of the same, as cut through at the line C, C.

Description 0f a steam chest, valve, cylz'neler anal appending apparatus, includ/ng my improvement, by reference to the Figs. 1, 2, anel 3, n the drawings-The letters used in this specification refer to the corresponding letters in all the Figs. l, 2 and 3.

A, is a part of a steam cylinder to which a steam chest B, is attached by means of the bolts a, a, a, a.

C is a common slide valve as now generally used and rests on the valve seat attached to the cylinder and covers the exhaust port D, the bars E, E, and the steam ports F,`F.

Gr is a stuffing box attached to the steam chest. y

H is a valve stem, and passes through the stufling box and is attached to the valve C by the nuts l), b, at each end of the valve C.

A. blank valve I is attached tothe back of the slide valve C by the screws J, J, or by other like means, and fastened so as to prevent the two valves (C and I) from separating, and thus fitted or fastened together they are compelled to move together.

The valve I is set so as to touch the inverted seat K and -is made steam tight by grinding the surfaces.

L is a false aperture thro-ugh the top of the steam chest which aperture is closed 4,907, dated Deeember 28, 184e.

I is made equal to the pressure of the atmosphere on the under side of the valve C, thus equalizing the atmospheric pressure, and operating friction from its inequality. This cap is also used to pour oil upon the upper side of the blank valve I, for the purpose of reducing friction and keeping it moist.

N N are covers on the sides ofthe steam chest and are attached to it by screws `and can be removed'to adjust or examine the valve.

O is the steam pipe.

P is the exhaust pipe, having a connection with the atmosphereor condenser as the case may be.

Q, is the span of the valve C.

The operation of the valve (meaning the valves C and I fastened together, and thus constituting the valve as above described) is as follows: The steam is admitted through the pipe O to the whole interior'of the steam chest B, 'and presses on all parts equally. But the pressure on the back of the valve now generally used without the blank valve I, causes it to adhere to the seat with such force as to produce great friction. The valve herein described is made to move backward and forward in the portions or area, to the area of the span Q (of the valve C) connected by the exhaust pipe with the atmosphere or condenser and the inverted seat K, bearing its due proportions to the wearing surface of the valve C resting on the seat attached to the cylinder-` and the valves (C and I) being so adjusted by the connections J J as to be made tov touch the seats and thus render them (the valves) steam tight-the pressure of the steam on one of the valves is neutralized by the pressure of the steam on the other, thus preventing friction and allowing the Whole valve (i. e. C and I combined as above described) to move as freely When under a great pressure as When t-here is no pressure at all. The surface of the blank valve I should always be made sufficiently long to allow the valve to perform its operations and not leave the edge of the seat.

What I claim as my invention and desire to secure by Letters Patent, is the following The described means of neutralizing the effect of the pressure of the steam (or fluid as the case may be) upon the backof the valves (C, and I) and equalizing the pressure of the atmosphere on the upper side of STEPHEN F. GATES. Witnesses:

HENRY B. STANTON, HENRY I). HOLLAND. 

